JP2012124543A - Speaker device and speaker arrangement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker device and speaker arrangement method capable of keeping an excellent sound field feeling with respect to the turning of a head of a listener.SOLUTION: A pair of speakers including a left speaker 21 and a right speaker 22 is arranged on a turning axis orthogonal plane to be substantially orthogonally crossed with a turning center axis Z when a listener 10 turns his/her head in a horizontal direction and also on a turning axis concentric circle 31 with the turning center axis Z as a center (a condition (A)) and at a point-symmetric position with respect to the turning center axis Z (a condition (B)). Consequently, even when the head of the listener 10 is turned in the horizontal direction with the turning center axis Z as a center, a distance from the left speaker 21 to a left ear 11 is allowed to be equal to a distance from the right speaker 22 to a right ear 12, so as to prevent a difference between left and right sound volumes.

Description

  The present invention relates to a speaker device and an arrangement method for reproducing a sound signal having at least two speakers.

  As a method for reproducing a sound signal such as music, stereophonic (stereophonic) reproduction using two or more speakers is widely used as the most common reproduction method. Stereo reproduction has a feature that it can provide a listener with a rich sense of sound field with left and right expansion, compared to monophonic reproduction in which sound signals are reproduced from a single speaker.

  In stereo reproduction, normally, when a pair of speakers are arranged at a position where the listener has a front spread angle of 30 degrees to reproduce stereo sound, the listener can experience a good stereo sound field. However, in an environment where in-vehicle audio is used, it is difficult to install a pair of left and right speakers at a front spread angle of 30 degrees for all passengers in the vehicle. For this reason, for example, Patent Documents 1 to 3 disclose a method of stereo reproduction by installing two speakers at the headrest position. FIG. 12 is an explanatory view showing a speaker installation position for in-vehicle audio disclosed in Patent Document 1, FIG. 13 is Patent Document 2, and FIG. 14 is Patent Document 3. A pair of speakers 2 and 3 are installed on the headrest 1. ing. By reproducing sound signals with the speakers 2 and 3 installed as shown in FIGS. 12 to 14, there is an effect that the passenger can enjoy music individually and an effect that the passenger feels the sound field.

JP 2001-95646 A Japanese Patent No. 3719690 JP 2001-298788 A

  Since the conventional speaker device and the arrangement method are configured as described above, when the listener turns his head while turning his head, a noticeable difference occurs in the sound volume reaching the left and right ears. As a result, there is a problem that the listener cannot experience a good stereo sound field because the sound image is biased toward a higher volume.

  Hereinafter, this problem will be specifically described with reference to the drawings. FIG. 15 is an explanatory diagram showing a coordinate system used for explaining the positional relationship between the listener and the speaker. FIG. 15 (a) is a plan view, FIG. 15 (b) is a front view, and FIG. ) Is a side view. In FIG. 15, a line passing through the left ear 11 and the right ear 12 of the listener 10 is taken as the X axis. The positions of the left ear 11 and the right ear 12 are the left and right ear canal entrances, respectively. On the X axis, the midpoint of the left ear 11 and the right ear 12 is set as the origin, and the center axis of rotation when the listener 10 turns the head facing the front in a natural posture through the origin is defined as the Z axis. . A line passing through the origin and orthogonal to the XZ plane is taken as the Y axis. The X axis is positive in the left direction (the direction of the left ear 11) as viewed from the listener 10, the Y axis is positive in the forward direction as viewed from the listener 10, and the Z axis is positive in the direction of the top of the head. However, it is practically difficult to precisely define such XYZ axes, and an error occurs between the XYZ axes on the definition as shown in FIG. 15 and the actual positional relationship. However, the tendency of the volume difference reaching the left ear 11 and the right ear 12 can be sufficiently grasped even if the XYZ axes in the definition and the actual positional relationship do not exactly match. The XYZ axes on the definition will be used.

Here, in order to quantitatively evaluate the volume of the listener 10 reaching the left ear 11 and the right ear 12, an index is defined by the following equation (1). From the equation (1), the LR ratio represents the volume difference reaching the left ear 11 and the right ear 12 in decibels.
LR ratio (dB) = ₁₀ Log ₁₀ (volume at left ear position / volume at right ear position) (1)

  Hereinafter, the relationship between the listener's head rotation and the LR ratio in the speaker arrangements of Patent Documents 1 to 3 will be shown by computer simulation. In this computer simulation, attention was paid not to be specific to a specific environment and a specific listener, and reflection and diffraction due to the room environment and a different head shape for each listener were ignored. The volume was assumed to attenuate in inverse proportion to the square of the distance.

  FIG. 16 is a graph showing the relationship between the listener's head rotation angle θ and the LR ratio obtained by Expression (1) in the speaker arrangements of Patent Documents 1 to 3. The horizontal axis represents the listener's head rotation angle θ, and the vertical axis represents the LR ratio. Also, the position coordinates (x, y, z) of the listener are represented by the left ear position (8 cm, 0 cm, 0 cm) and the right ear position (−8 cm, 0 cm, 0 cm). Evaluation was performed by setting as follows.

In the techniques disclosed in Patent Documents 1 and 2, since there is no difference in speaker arrangement, the coordinates of the left speaker position are (15 cm, −10 cm, 0 cm), and the coordinates of the right speaker position are (−15 cm, −10 cm, 0 cm). It was. This arrangement assumes that the surface of the headrest 1 is 10 cm behind the position of the listener's ear, and a pair of speakers 2 and 3 are installed on the surface of the headrest 1 with an interval of 30 cm. The result in this case is the solid line 4 shown in FIG.
In the technique disclosed in Patent Document 3, the coordinates of the left speaker position are (15 cm, −15 cm, 0 cm), and the coordinates of the right speaker position are (−15 cm, −15 cm, 0 cm). In this arrangement, the surface of the headrest 1 is 10 cm behind the listener's ear position, and a pair of speakers 2 and 3 are installed with the driving surface facing upward at a distance of 30 cm on the top surface of the headrest 1 5 cm behind. Assuming that The result in this case is the broken line 5 shown in FIG.

  From FIG. 16, it can be seen that with the speaker arrangements of Patent Documents 1 to 3, the listener's head rotation angle is only about 30 degrees and the LR ratio is about 3 dB, resulting in a very large left-right volume difference. If the left and right volume difference is 3 dB, the perceived sound image is greatly biased, and the listener cannot obtain a good sound field feeling. That is, the techniques of Patent Documents 1 to 3 have a problem that the sound field feeling is impaired by slight head rotation.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a speaker device and a speaker arrangement method that can maintain a good sound field feeling with respect to the listener's head rotation. .

  In the speaker device according to the present invention, the pair of speakers are on a plane substantially orthogonal to the rotation center axis when the listener rotates the head in the left-right direction, and on a concentric circle centered on the rotation center axis. These are arranged at point-symmetric positions with respect to the rotation center axis.

  In the speaker arrangement method according to the present invention, the pair of speakers are on a plane substantially orthogonal to the rotation center axis when the listener rotates the head in the left-right direction, and on a concentric circle centering on the rotation center axis. Thus, it is arranged at a point-symmetrical position with respect to the rotation center axis.

  According to the present invention, the pair of speakers are rotated on a plane substantially orthogonal to the rotation center axis when the listener rotates the head in the left-right direction, and on a concentric circle centered on the rotation center axis. Since it is arranged at a point-symmetrical position with respect to the central axis, a good sound field feeling can be maintained without causing a difference in sound volume between the left and right ears when the listener's head rotates. A speaker device and a speaker arrangement method can be provided.

In the speaker apparatus according to Embodiment 1 of the present invention, it is an explanatory diagram showing speaker placement positions. It is a figure explaining the detail of the rotating shaft concentric circle shown in FIG. 6 is a graph showing the relationship between the listener's head rotation angle and the volume difference (LR ratio) reaching the left and right ears in the speaker arrangement of the first embodiment. 6 is a plan view showing a state where the front position of the listener is deviated by 45 degrees in the speaker arrangement according to Embodiment 1. FIG. FIG. 3 is a side view showing a state where the listener's head rotation center axis is deviated by 45 degrees in the speaker arrangement of the first embodiment. It is a side view which shows the example of arrangement | positioning at the time of applying the speaker arrangement | positioning of Embodiment 1 to vehicle-mounted audio. It is a side view which shows the example of arrangement | positioning at the time of applying the speaker arrangement | positioning of Embodiment 1 to vehicle-mounted audio. In the speaker apparatus which concerns on Embodiment 2 of this invention, it is explanatory drawing which shows a speaker arrangement position. 6 is a graph showing the relationship between the head rotation angle and the volume difference (LR ratio) reaching the left and right ears when the listener moves 5 cm to the left from the origin in the speaker arrangement of the second embodiment. It is a front view which shows the state which the listener moved 5 cm to the left from the origin in the speaker arrangement | positioning of Embodiment 2. FIG. 6 is a front view showing a state in which the listener has moved 5 cm to the left from the origin in the speaker arrangement of Embodiment 1. FIG. It is explanatory drawing which shows the speaker installation position for vehicle-mounted audio disclosed by patent document 1. FIG. It is explanatory drawing which shows the speaker installation position for vehicle-mounted audio disclosed by patent document 2. FIG. It is explanatory drawing which shows the speaker installation position for vehicle-mounted audio disclosed by patent document 3. FIG. It is explanatory drawing which shows the coordinate system used in order to demonstrate the positional relationship of a listener and a speaker. It is the graph which showed the relationship between the listener's head rotation angle in the speaker arrangements of Patent Literatures 1 to 3 and the volume difference (LR ratio) reaching the left and right ears.

Embodiment 1 FIG.
1A and 1B are explanatory views showing the arrangement positions of the speaker devices (the left speaker 21 and the right speaker 22) according to Embodiment 1 of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a front view. FIG. 1 and FIG. 1C are side views. In this embodiment, the same coordinate system as that shown in FIG. 15 is used.
In FIG. 1, left and right sound signals output from a sound signal reproduction device such as a CD player (not shown) are radiated as sound waves by a left speaker 21 and a right speaker 22 via a power amplifier (not shown). The left and right sound signals output from the sound signal playback device are input to the power amplifier via a device that performs arbitrary processing, such as processing that improves the sense of spread, processing that improves frequency characteristics, and processing that adjusts the volume. You may comprise. Further, although the speakers 21 and 22 are illustrated as cone type speakers, other types of speakers may be used.

In the present embodiment, the arrangement of the left speaker 21 and the right speaker 22 has the following conditions.
(A) The left speaker 21 and the right speaker 22 are positioned on a concentric circle (hereinafter referred to as a rotational axis concentric circle 31) centered on the rotation center axis Z of the head. (B) The positions of the left speaker 21 and the right speaker 22 are It is point-symmetric with respect to the center of the rotation axis concentric circle 31, that is, the rotation center axis Z. The height position in the Z-axis direction of the left speaker 21 and the right speaker 22 and the arrangement interval thereof are not particularly limited. The arrangement of FIG. 1 is an example.

  Here, the rotation axis concentric circle 31 of the condition (A) will be described. 2A and 2B are diagrams for explaining details of the concentric circle 31 of the rotation shaft shown in FIG. 1, FIG. 2A is a plan view, FIG. 2B is a front view, and FIG. 2C is a side view. First, a plane obtained by translating the XY plane up and down in the Z-axis direction is defined as a rotation axis orthogonal plane. The magnitude (distance) of the translation indicated by the arrows in the figure is arbitrary. In FIG. 2, an example of the rotation axis orthogonal plane that has been translated upward is shown as the upper rotation axis orthogonal plane 32, and an example of the translation in the lower direction is shown as the lower rotation axis orthogonal plane 33. The rotation axis concentric circle 31 is a rotation axis orthogonal plane centered at a point where the rotation axis orthogonal plane exemplified as the upper rotation axis orthogonal plane 32 or the lower rotation axis orthogonal plane 33 and the rotation center axis Z of the head intersect. It is the upper circle. In addition, the radius of the rotating shaft concentric circle 31 is arbitrary.

  As shown in FIG. 1, when the left speaker 21 and the right speaker 22 are arranged so as to satisfy the conditions (A) and (B), even if the listener 10 shakes his / her head left and right (the head rotates) ) The distance from the left speaker 21 to the left ear 11 and the distance from the right speaker 22 to the right ear 12 are always equal. The reason for this will be described below.

If the radius of the head of the listener 10 is r, and the rotation angle of the head around the Z axis is θ, the coordinates of the left ear 11 before the head rotation are (r, 0, 0), The coordinates are (−r, 0, 0), the coordinates of the left ear 11 after rotation are (rCOSθ, SINθ, 0), and the coordinates of the right ear 12 are (−rCOSθ, −SINθ, 0). However, the rotation angle θ is assumed to be 90 degrees or less, and the head rotation is assumed to be clockwise (clockwise).
On the other hand, the coordinates of the left speaker 21 can be expressed as (x _L , y _L , z _L ), and the coordinates of the right speaker 22 can be expressed as (x _R , y _R , z _R ). Since the left speaker 21 and the right speaker 22 are arranged at point-symmetric positions on the plane orthogonal to the rotation axis, the following expression (2) is established.
x _L = −x _R = x _s
y _L = −y _R = y _s (2)
z _L = z _R = z _s
However, x _s , y _s , and z _s are constants uniquely determined by the positions of the speakers 21 and 22.

Using equation (2), the distance from the left ear 11 of the listener 10 to the left speaker 21 after rotating the head by the rotation angle θ can be expressed by the following equation (3). On the other hand, the distance from the right ear 12 of the listener 10 to the right speaker 22 can be expressed by Expression (4).

From equations (3) and (4), it can be confirmed that the distance from the left speaker 21 to the left ear 11 and the distance from the right speaker 22 to the right ear 12 are equal. The same result is obtained when the head is rotated counterclockwise.
Since the sound volume attenuates in inverse proportion to the square of the distance, if the distance from the speaker to the ear is equal, the sound volume is the same on the left and right. That is, according to the present embodiment, even if the listener 10 freely rotates his / her head, there is no difference in the volume of the sound reaching the left ear 11 and the right ear 12, and a good stereo sound field feeling Can be maintained.

  Next, the effect of the above-described embodiment will be supplementarily explained by computer simulation. FIG. 3 is a graph showing the relationship between the head rotation angle θ of the listener 10 and the LR ratio obtained by the equation (1) in the speaker arrangement of the first embodiment, and the horizontal axis represents the head rotation of the listener 10. The angle θ is shown, and the LR ratio is shown on the vertical axis. Similarly to the computer simulations of Patent Documents 1 to 3 described above, in this embodiment, the position of the left ear 11 of the listener 10 is (8 cm, 0 cm, 0 cm), and the position of the right ear 12 is (−8 cm, 0 cm). , 0 cm). The position of the left speaker 21 is (15 cm, 0 cm, 20 cm), and the position of the right speaker 22 is (-15 cm, 0 cm, 20 cm). The result of the computer simulation under this condition is shown as a solid line 41. From FIG. 3, it can be confirmed that in the speaker arrangement of the present embodiment, the LR ratio does not change at all with respect to the listener's 10 head rotation.

  Also, the case where the XYZ axes in the actual stereo reproduction environment are deviated from the defined XYZ axis assumed positions is evaluated. Here, even if each axis is shifted, it is difficult to assume that the XY plane is greatly shifted (for example, 45 degrees), but the front position where the listener 10 faces the front is considered to have individual differences for each listener. . For this reason, the LR ratio with respect to the head rotation when the X-axis positive direction is shifted 45 degrees in the Y-axis positive direction was also evaluated as the front position shift. FIG. 4 is a plan view showing a state where the front position of the listener 10 is shifted by 45 degrees. At this time, the defined X axis and Y axis are also shifted by 45 degrees to become the X ′ axis and the Y ′ axis, but the rotation center axis Z of the head does not move. The result in this case was a solid line 41 shown in FIG. Even when the Y-axis positive direction is deviated in the X-axis positive direction, the same positional relationship is obtained, so the same result is obtained.

  Furthermore, in a realistic stereo reproduction environment, it is conceivable that the posture changes by changing the angle of the reclining seat on which the listener 10 is seated, and the rotation center axis Z of the head deviates from the definition Z axis. . Since the reclining angle is about 45 degrees at most in the normal use range, the LR ratio with respect to the head rotation when the Z-axis positive direction is shifted 45 degrees in the Y-axis negative direction was also evaluated. FIG. 5 is a side view showing a state in which the head rotation center axis Z of the listener 10 is shifted by 45 degrees. At this time, the rotation center axis Z of the head is also shifted by 45 degrees to become the Z ′ axis. The result in this case is a broken line 42 shown in FIG.

From the solid line 41 in FIG. 3, it can be confirmed that the LR ratio does not change at all with respect to the head rotation of the listener 10 in the speaker arrangement as shown in FIG. Further, as shown in FIG. 4, it can be confirmed that the LR ratio does not change at all even if the front position (X axis or Y axis) is shifted by 45 degrees. Further, as shown in FIG. 5, even if the Z axis is deviated by 45 degrees, the LR ratio is within 3 dB within the range of the head rotation angle θ from 0 degrees to 60 degrees from the broken line 42 in FIG. Can be confirmed.
Therefore, the loudspeaker arrangement according to the present embodiment is extremely robust with respect to the listener's 10 head rotation and can stably provide a good sound field feeling. Moreover, even if there is a deviation within 45 degrees in the rotation center axis Z of the head, a sufficiently good effect can be obtained.

The speaker arrangement according to the present embodiment is very effective in an environment where the position and front direction of the listener can be substantially specified, such as in-vehicle audio. When applied to in-vehicle audio, for example, it can be easily realized by arranging a pair of left and right speakers on the ceiling according to the conditions (A) and (B).
A pair of left and right speakers may be arranged on the headrest. 6 and 7 are side views showing an arrangement example when the speaker arrangement of the first embodiment is applied to in-vehicle audio. As shown in FIG. 6, the headrest 52 attached to the seat 51 is shaped to protrude to the front of the listener 10, and the headrest 52 is in a position corresponding to the upper part of the left ear 11 and the right ear 12 of the listener 10. The left speaker 21 and the right speaker 22 may be installed.
Alternatively, as shown in FIG. 7, the arm 53 attached to the seat 51 is extended to a shape protruding to the front of the listener 10, and the left speaker 21 and the right speaker 22 are fixed to the tip of the arm 53. You may make it hold | maintain in the position corresponded above the ear | edge 11 and the right ear 12. FIG. The arm 53 may be movable or non-movable.

  In the installation method in which the speaker arrangement is applied as shown in FIGS. 6 and 7, the application target is not limited to the in-vehicle audio, but can be applied to an apparatus having a seat prepared in advance, for example, a racing game apparatus in a game center. . In addition to this, the headrest of the sofa is shaped like the headrest 52 shown in FIG. 6 to install the left speaker 21 and the right speaker 22, or the arm 53 as shown in FIG. A right speaker 22 may be installed. As a result, a good stereo sound field can be provided to the listener even in a living room, theater, and other public spaces.

  Note that the left speaker 21 and the right speaker 22 may be installed with the speaker drive surface facing in any direction. However, since the speakers generally have different directivities for each frequency, the difference in intensity between the frequencies can be alleviated and the sound quality can be improved by directing the speaker drive surface to the listener direction as much as possible. Therefore, for example, when the left speaker 21 and the right speaker 22 are arranged on the lower rotation axis orthogonal plane 33 in FIG. 2, the speaker drive surface is installed upward.

  As described above, according to the first embodiment, the pair of speakers including the left speaker 21 and the right speaker 22 rotate substantially orthogonal to the rotation center axis Z when the listener 10 rotates the head in the left-right direction. It is on the axis orthogonal plane and on the rotation axis concentric circle 31 centered on the rotation center axis Z (condition (A)), and is arranged at a point-symmetrical position (condition (B)) with respect to the rotation center axis Z. It was configured as follows. For this reason, the sound volume difference between the sounds reaching the left ear 11 and the right ear 12 does not occur with respect to the head rotation of the listener 10, and a good sound field feeling can be maintained.

  In the first embodiment, the left speaker 21 and the right speaker 22 are connected to a sound signal reproducing device that reproduces music or the like. However, the present invention is not limited to this, and for example, an active sound field control device that reduces noise. You may apply to. Here, the noise is any sound that is unnecessary for the listener, and for example, traveling noise, engine noise, sound or speech generated in the vicinity, environmental sound, and the like are targeted. In a noisy environment, by playing a sound signal that cancels noise from two or more speakers arranged according to the present embodiment, the robustness is improved with respect to the rotation of the listener's head, and the noise reduction effect Can be provided stably.

Embodiment 2. FIG.
8A and 8B are explanatory views showing the arrangement positions of the speaker devices (the left speaker 21a and the right speaker 22a) according to Embodiment 2 of the present invention. FIG. 8A is a plan view and FIG. 8B is a front view. FIG. 8 and FIG. 8C are side views. The second embodiment has the following conditions in addition to the speaker arrangement conditions (A) and (B) described in the first embodiment.
(C) The left speaker 21a and the right speaker 22a are arranged so that the line 34 connecting the left speaker 21a and the right speaker 22a and the X axis connecting the left ear 11 and the right ear 12 are parallel to each other. (D) The left speaker 21a And the right speaker 22a are arranged so that the distance (distance) between the left ear 11 and the right ear 12 of the listener 10 is equal to the distance (distance). Since this is the same as the first embodiment, the description thereof is omitted.

  As shown in FIG. 8, when the left speaker 21a and the right speaker 22a are arranged so as to satisfy the conditions (A) to (D), the listener 10 rotates his / her head as in the first embodiment. However, there is no volume difference between the sound reaching the left ear 11 and the sound reaching the right ear 12. Further, when the listener 10 faces the front direction, even if the listener 10 moves left and right (in the X-axis direction), the distance from the left speaker 21a to the left ear 11 and from the right speaker 22a to the right ear 12 Is the same distance. The reason for this will be described below.

If the radius of the head of the listener 10 is r, the position of the left ear 11 is (r, 0, 0), and the position of the right ear 12 is (−r, 0, 0). Further, the position of the left speaker 21a according to the present embodiment is (r, 0, z _s ), and the position of the right speaker 22a is (−r, 0, z _s ). At this time, the distance from the left ear 11 to the left speaker 21a after the head has moved to the left by the distance d can be expressed by the following equation (5). On the other hand, the distance from the right ear 12 of the listener 10 to the right speaker 22a can be expressed by the following equation (6).

From the above equations (5) and (6), it can be confirmed that the distance from the left speaker 21a to the left ear 11 and the distance from the right speaker 22a to the right ear 12 are equal. The same result is obtained even if the head moves to the right by the distance d.
Since the sound volume attenuates in inverse proportion to the square of the distance, if the distance from the speaker to the ear is equal, the sound volume is the same on the left and right. That is, according to the present embodiment, even if the listener 10 moves to the left and right, there is no difference in the volume of the sound reaching the left ear 11 and the right ear 12, and a good stereo sound field feeling is maintained. be able to.

  Next, the effect of the above-described embodiment will be supplementarily explained by computer simulation. FIG. 9 shows the relationship between the head rotation angle θ and the LR ratio obtained by equation (1) when the head of the listener 10 is moved 5 cm to the left from the origin in the speaker arrangement of the second embodiment. The horizontal axis represents the head rotation angle θ of the listener 10, and the vertical axis represents the LR ratio. FIG. 10 is a front view showing a state in which the head of the listener 10 is moved 5 cm to the left from the origin in the arrangement of the left speaker 21a and the right speaker 22a according to the second embodiment. Z also shifts by 5 cm to become the Z ′ axis. As shown in FIG. 10, since the head of the listener 10 is moved to the left by 5 cm from the origin, the position of the left ear 11 of the listener 10 is (13 cm, 0 cm, 0 cm), and the position of the right ear 12 is (-3 cm, 0 cm, 0 cm). The position of the left speaker 21a is (8 cm, 0 cm, 20 cm), and the position of the right speaker 22a is (-8 cm, 0 cm, 20 cm). The result of the computer simulation under these conditions is shown as a solid line 61 in FIG.

  For comparison, the relationship between the head rotation angle θ and the LR ratio when the head is moved 5 cm to the left in the speaker arrangement of the first embodiment is also shown as a broken line 62. FIG. 11 is a front view showing a state in which the head of the listener 10 has been moved 5 cm to the left from the origin in the arrangement of the left speaker 21 and the right speaker 22 according to the first embodiment. Z also shifts by 5 cm to become the Z ′ axis. As shown in FIG. 11, since the head of the listener 10 has moved to the left by 5 cm from the origin, the position of the left ear 11 of the listener 10 is (13 cm, 0 cm, 0 cm), and the position of the right ear 12 is (-3 cm, 0 cm, 0 cm). The speaker arrangement is the same as in the first embodiment, and the position of the left speaker 21a is (15 cm, 0 cm, 20 cm), and the position of the right speaker 22a is (-15 cm, 0 cm, 20 cm). The result of the computer simulation under this condition is shown as a broken line 62 in FIG.

As shown by the broken line 62 in FIG. 9, in the speaker arrangement of the first embodiment, when the listener 10 moves left and right, an offset of the left and right volume difference of about 1 dB occurs regardless of the head rotation. On the other hand, as shown by the solid line 61, in the speaker arrangement of the second embodiment, the left and right volume difference offset does not occur even if the listener 10 moves left and right, and the head rotation also occurs. It can be confirmed that the LR ratio hardly changes.
Therefore, the loudspeaker arrangement of the present embodiment increases the robustness not only with respect to the listener's 10 head rotation but also with respect to left and right movements, and can provide a better sound field feeling more stably. .

  As described above, according to the second embodiment, the pair of speakers including the left speaker 21a and the right speaker 22a rotate substantially orthogonal to the rotation center axis Z when the listener 10 rotates the head in the left-right direction. They are arranged on a plane orthogonal to the axis and on a rotation axis concentric with the rotation center axis Z as the center (condition (A)) and in a point-symmetric position (condition (B)) with respect to the rotation center axis Z. In addition, the line 34 connecting the left speaker 21a and the right speaker 22a and the line connecting the left ear 11 and the right ear 12 of the listener 10 are substantially parallel (condition (C)), and the left speaker 21a and the right speaker 22a The interval and the interval between the left ear 11 and the right ear 12 are configured to be arranged at substantially the same position (condition (D)). For this reason, even if the head rotates, there is no difference in the volume of the sound that reaches the left and right ears. On the other hand, a good sound field feeling can be maintained.

  DESCRIPTION OF SYMBOLS 1 Headrest, 2,3 A pair of speaker, 10 listeners, 11 Left ear, 12 Right ear, 21,21a Left speaker, 22, 22a Right speaker, 31 Concentric circle of rotation axis, 32 Upper plane of orthogonal rotation axis, 33 Lower rotation Axis orthogonal plane, 34 Line connecting speakers 21a, 22a, 51 seats, 52 headrest, 53 arms.

Claims (10)

In a speaker device that reproduces a sound signal using at least a pair of speakers,
The pair of speakers are on a plane substantially orthogonal to the rotation center axis when the listener rotates the head in the left-right direction, and on a concentric circle with the rotation center axis as the center, with respect to the rotation center axis. The speaker device is arranged at a point-symmetrical position.   The speaker device according to claim 1, wherein the distance between the pair of speakers and the distance between the left and right ears of the listener are substantially the same.   The speaker device according to claim 1 or 2, wherein a line connecting the pair of speakers and a line connecting the left and right ears of the listener are substantially parallel.   The speaker device according to any one of claims 1 to 3, wherein the pair of speakers are arranged above the listener's ear position and the speaker driving surface faces downward.   The speaker device according to any one of claims 1 to 3, wherein the pair of speakers are arranged below the listener's ear position and the speaker drive surface faces upward. In a speaker arrangement method of a speaker device that reproduces a sound signal using at least a pair of speakers,
The pair of speakers are on a plane substantially orthogonal to the rotation center axis when the listener rotates the head in the left-right direction, and on a concentric circle with the rotation center axis as the center, with respect to the rotation center axis. And a speaker arrangement method, wherein the speaker is arranged in a point-symmetrical position.   The speaker arrangement method according to claim 6, wherein the distance between the pair of speakers and the distance between the left and right ears of the listener are substantially the same.   The speaker arrangement method according to claim 6 or 7, wherein a line connecting the pair of speakers and a line connecting the left and right ears of the listener are substantially parallel.   The speaker placement method according to any one of claims 6 to 8, wherein the pair of speakers are disposed above the listener's ear position and the speaker drive surface is directed downward.   The speaker placement method according to any one of claims 6 to 8, wherein the pair of speakers are disposed below the listener's ear position and the speaker drive surface is directed upward.

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